A. Carefully check your model to make sure this is a suitable filter for your air purifier. This filter is suitable for air purifiers of models such as Core 400S and Core 400s - RF, and its working effect is similar to that of the original filter of the device. B. High cost - effectiveness: The cost - effective set can help you save a certain amount of cost for your annual air purification needs. It has a relatively high level of filtration performance and can be used for a long time. It is recommended to replace it every 6 - 12 months. Using an old filter may reduce the efficiency of the air purifier. C. H13 True High - Efficiency Particulate Air (HEPA) technology: It uses a relatively high - grade true high - efficiency air filtration material with a 360 - degree filtration function, which can capture about 99% of particles with a diameter as low as 0.3 microns. It can improve the air quality in your room, make your breathing and sleeping more comfortable, and help avoid runny noses and sneezing. D. Efficient odor removal: The activated carbon filter can filter out bad odors and smoke, including volatile organic compounds (VOCs), tobacco smoke, cooking odors, and pet odors, which can reduce indoor odors to a certain extent and create a relatively pure air environment. E. Easy to install: Suitable for Core 400S, no need to cut the high - efficiency air filter. You can replace the old filter without other tools, which can save some time and is quite convenient to use. F. Color: White G. Material: Composite material H. Package content: 1 piece I. Only the above package content is included, and other items are not included. J. Note: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the actual one. The measurement tolerance is +/- 1 - 3 cm.